It's not possible to by channel set input channels as Pre/Post fader individually in a mix (as expressed in the Hardware Manual Online), but it is possible to get an affect like this using two (2) buses.
For Example:
If we are setting channel one to be "post fader" on a mix and send all of the rest of the channels on the mixer "Pre Fader," you can A.) use a Pre Fader Aux mix, and send that mix to B.) a Globably post fader Matrix.
What you would do is send all channels but channel 1 to the Aux mix and then send only the Aux send and channel 1 to the Matrix mix. In that regard, you now have the ability to turn channel 1 up and down in the Main mix and it will be affected in the matrix, while all pre-fader channels in the Auxiliary will be unaffected.
